Hydraulic cam device



nited Sttes Patent HYDRAULIC CAM DEVICE Eugene S. Wassel, La Grange, and Mitchell J. Shoelson, Hometown, Ill., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Application February 8, "1957, Serial No. 639,130

1 Claim. (Cl. I4- 88) Our invention relates to a discharge gas motor for a gun and more particularly to a device for linking cam follower rf rods in the'motor.

This application is presented for copending consideration with the application entitled Gas Motor, by Samuel Altschuler, Serial No. 639,151, filed February 8, 1957.

The shaft of a discharge gas motor for a gun includes an even number of rods slidably disposed in radial bores and provided with roller tips. The rods are alternately disposed in positions wherein the rollers respectively project from the shaft or are inclosed therein. The shaft is disposed for axial reeiprocation responsive to discharge gases from the gun, and a series of cam grooves are provided in the stator of the motor for engagement with the rods when in projecting positions to rotate the shaft through the pitch angle of the rods responsive to the reciprocation. Each of the cam grooves includes a ramp which engages the projecting rods for retraction thereof into the shaft after being rotated one pitch.

It is an object of our invention to provide a link device between the rods for reversing the projection of the sets from the shaft responsive to the rotation.

Another object of our invention is` to provide a hydraulic link device between the rods.

Other aims and objects of our -invention will appear from the following description thereof.

In carrying out our invention, the shaft is provided with an axial chamber and tubes connecting the chamber to the bores. The rods are disposed in the bores with the al ternate rollers respectively inclosed in the shaft and projecting therefrom and the chambers, the tubes, and the bores behind the rods are filled with hydraulic fluid.

After the shaft is rotated one pitch, the ramps engage the rollers of the projecting set of followers and cause the rods upon which the rollers are mounted to be forcibly retracted into the shaft. Displacement of the virtually incompressible hydraulic iiuid by the retracted rollers causes the alternate set of rollers to be actuated outwardly into engagement with the succeeding ones of the cam paths for the subsequent reciprocal cycle.

For a more complete understanding, reference is directed to the following description and the accompanying drawing in which:

Fig. 1 is an elevation of a discharge gas motor; and

Fig. 2 is a view along line 2-2 of Fig. 1.

Accordingly, a gun 12 having a recoil unit 14, and barrels 16 secured therein is provided with a motor 18 including a stator 20 secured to the recoil unit. Stator 20 includes a cylinder 22, and a piston 23 is biased by a spring 21 to a battery position in the cylinder. Piston 23 is provided with a shaft 24. The cylinder communicates with barrels 16 by means of conventional gas ports, one of which is shown in Fig. l at 25, for longitudinal actuation of shaft 24 against the bias of spring 21, responsive to gases from the discharge of cartridges in the barrel. Shaft 24 is provided with a ilange 28 including six bores 32 spaced 60 apart. A rod 30 is slidingly dis- ,s 2,902,869 Patented Sept. 8, 1959 rollers 34 projecting from and retracted into flange 28.

Chamber 36, tubes 38, and the portions of the bores 32 behind rods 30 are filled with hydraulic uid 39. The inside of stator 20 is provided with three individual cam paths 40 which are U-shaped with curved portions 42 forwardly disposed and which slidingly receive the rollers 34 when in the projecting positions. The pitch of the adjacent legs of adjacent cam paths, as well as` the pitch of the legs of individual cam paths, is the same as the angular displacement of the rods 30 and rollers 34, so

; that the rollers 34 may engage successive ones of the cam paths 40 when flange 28 is rotated. Each cam path 40 is provided with a ramp 44 that causes the roller 34 that is projecting into the cam path to ride out thereof after moving around curved portion 42 with the hydraulic fluid displaced thereby movingthe other ones of the rollers 34 outwardly into engagement with the succeeding ones of the cam paths 40 as the flange 28 is rotated by engagement of the projecting rollers 34 with the curved part of the cam path 42 and is reciprocated axially responsive to actuation by the piston 23 through piston rod 24. Thus, when gun 12 lis discharged, the resulting gases enter cylinder 22 to energize piston 23 for movement therein and compress the biasing spring. Such movement of piston 23 is transferred to flange 28 through shaft 24. As has been explained, alternate ones of the rollers 34 project outwardly from the bores 32 in iiange 28 to be slidingly received by the cam paths 40 while the remaining ones of the rollers are retracted within the ange. Therefore, during movement of flange 28 of piston 23, the projecting rollers are moved along the cam paths 40 to the curved portions 42 which cause the flange to rotate one half the pitch of the curved portions. Flange 28 continues to rotate through inertia until the projecting rollers 34 are moved past the dead centers of the curved portions 42 and is rotated around the curved portions and the remaining portion of the pitch during the biased return of the iiange to normal position.

During the return stroke of ange 28, the projecting rollers 34 engage the ramps 44 after passing around curved portion 42 whereby such rollers are moved into the corresponding bores 32. The retraction of the extending roilers 34 cause the rods 30 mounted thereto to be moved into the cooperating bores 32 against the hydraulic fluid therein. The pressure applied against the hydraulic uid causes the alternate ones of the rollers 34 to be projected from flange 28 into the succeeding ones of the cam paths 40 which are now aligned therewith for rotating such ange another pitch when gun 12 is red again and flange 28 is reciprocated another cycle.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claim is intended to include such variations.

We claim:

In a motor including a hollow stator, a shaft with a cylindrical flange disposed for linear and rotational movement in the stator, means for moving the flange linearly in the stator, a plurality of U-shaped cam paths each including a pair of parallel leg portions connected by a forwardly disposed semicircular portion, the cam paths being disposed around the inside of the stator so that the leg portions are equidistantly and parallelly spaced therein, and a plurality of rollers equal to twice the number of the cam paths mounted in the ange for radial reciprocation therein, said rollers being spaced in the ange for simultaneous alignment with the leg portions of the cam paths and being alternately and simultaneously reciprocable between projecting positions for engagementwith the corresponding ones of the leg portions and retracted positions within the flange and clear of the cam paths, a device for actuating alternate ones of the rollers to the retracted positions thereof during nal movement of said flange in each linear reciprocation thereof and sirnultane# ously actuating the remaining ones of the rollers to the projecting positions, said device including a chamber axially disposed in the shaft, bores radially disposed in the ange for respective communication with the rollers, tube means providing intercommunication between said bores and chamber, a rod coaxially mounted to each of the rollers and slidingly disposed in each of said bores in back of the rollers for reciprocation therewith, a ramp portion similarly terminating each of the cam paths for engageably moving the rollers in the projecting positions to the retracted positions thereof after circuiting the cam paths during linear reciprocation of the flange, and a displaceable volume of hydraulic fluid filling said chamber and said bores in back of said rods when the rollers are alternately disposed in the projecting and retracted positions for converting movement of the alternate ones of the rollers to the retracted position to simultaneous opposite movement of the remaining ones of the rollers to the projecting positions for engagement With the ends of the earn paths opposite those terminated by said ramps to thereby rotate said ange one pitch distance during circuit of the projecting position rollers in the cam paths during the succeeding linear reciprocation of the ange.

References Cited in the file of this patent UNITED STATES PATENTS 582,244 Tuckeld May 11, 1897 763,133 Wheeler June 21, 1904 FOREIGN PATENTS 521,931 Canada Feb. 21, 1956 

